Deleted TP files
Deleted all TP tables from mysql
Download TP fresh from, well, here
Imported mysql freshly dumped from live site
Is there any log file or something I can offer to help?
Ok, something doesn't sound right there. So to be sure,
1: Copy files from live site to test site
2: Create a blank (empty) database and give it a different name from your live one.
3: Import copy of live database in to new one.
4: Make sure testsite is looking at you new database by changing it in the Settings.php file
5: Run repair_settings.php
Make sure all is working.
6: Uninstall Tinportal
7: Install new version Tinyportal
See if it all works as expected.